RRC ID 5789
Author Mizutani M, Naganuma T, Tsutsumi K, Saitoh Y.
Title The syncytium-specific expression of the Orysa;KRP3 CDK inhibitor: implication of its involvement in the cell cycle control in the rice (Oryza sativa L.) syncytial endosperm.
Journal J. Exp. Bot.
Abstract During rice (Oryza sativa L.) seed development, the primary endosperm nucleus undergoes a series of divisions without cytokinesis, producing a multinucleate cell, known as a syncytium. After several rounds of rapid nuclear proliferation, the syncytium ceases to undergo mitosis; thereafter, the syncytium is partitioned into individual cells by a specific type of cytokinesis called cellularization. The transition between syncytium and cellularization is important in determining the final seed size and is a model for studying the cell cycle and cytokinesis. The involvement of cyclin-dependent kinase (CDK) inhibitors (CKIs) in cell cycle control was investigated here during the transition between syncytium and cellularization. It was found that one of the rice CKIs, Orysa;KRP3, is strongly expressed in the caryopsis at 2 d after flowering (DAF), and its expression is significantly reduced at 3 DAF. The other CKI transcripts did not show such a shift at 2 DAF. In situ hybridization analysis revealed that Orysa;KRP3 is expressed in multinucleate syncytial endosperm at 2 DAF, but not in cellularized endosperm at 3 DAF. Two-hybrid assays showed that Orysa;KRP3 binds Orysa;CDKA;1, Orysa;CDKA;2, Orysa;CycA1;1, and Orysa;CycD2;2. By contrast, Orysa;CDKB2;1 and Orysa;CycB2;2 do not show binding to Orysa;KRP3. Orysa;KRP3 was able to rescue yeast premature cell division due to the dominant positive expression of mutant rice CDKA;1 indicating that Orysa;KRP3 inhibited rice CDK. These data suggest that Orysa;KRP3 is involved in cell cycle control of syncytial endosperm.
Volume 61(3)
Pages 791-8
Published 2010-3
DOI 10.1093/jxb/erp343
PII erp343
PMID 19933315
PMC PMC2814109
MeSH Cell Cycle / genetics* Cyclin-Dependent Kinase Inhibitor Proteins / genetics* Cyclin-Dependent Kinase Inhibitor Proteins / metabolism Cyclin-Dependent Kinases / antagonists & inhibitors Cyclins / metabolism Endosperm / cytology* Endosperm / genetics Endosperm / growth & development Flowers / genetics Gene Expression Profiling Gene Expression Regulation, Plant* Genes, Plant / genetics Giant Cells / cytology Giant Cells / metabolism* Organ Specificity / genetics Oryza / anatomy & histology Oryza / cytology Oryza / genetics* Plant Proteins / genetics* Plant Proteins / metabolism Protein Binding RNA, Messenger / genetics RNA, Messenger / metabolism Saccharomyces cerevisiae / cytology
IF 5.83
Times Cited 21
Yeast FY12137 FYP424